The present invention relates generally to the manufacture of articles from an elongated continuous strip, and more particularly concerns an improved apparatus and method for producing tapes to be sewn to brassieres in the manufacture thereof.
Prior to the present invention considerable time and effort had to be expended in order to produce the individual tapes that are joined to the rear portion of a brassiere. In the manufacture of this type of wearing apparel, or undergarment, one tape is utilized having hooks thereon and the other tape having eyes thereon, which fastening elements are coupled together in adjusted relationship in a manner well known. In order to manufacture these tapes previously, after they were cut from a continuous strip, the spaced apart ends had to be hand sewn in order to join together the overlapping flexible layers of material from which the tape is formed.
Applicants have now discovered that it is possible to utilize ultrasonic vibratory energy to be able to form these tapes on a continuous basis automatically. The flexible layers of material from which the tapes are formed, are generally woven and have a sufficient synthetic composition, generally at least thirty percent, to be capable of welding with ultrasonic energy. One of the problems faced by the inventors is that the tape included a body portion comprised of various overlapping layers as well as a pair of tabs which similarly contained overlapping layers of fabric.
Accordingly, conventional ultrasonic welding techniques in which the strip of tape was interposed between a horn and anvil between the forward edge and rear edge of the strip would effectuate the welding of the individual overlapping pair of tabs together. This would be unacceptable in that the tabs are subsequently utilized to have positioned therebetween a portion of the garment to which they are joined. Faced with this problem, the applicants discovered that it is possible to interpose between the tabs an insulation element capable of being readily severed and having the ability for transmitting therethrough ultrasonic vibratory energy. This permits the individual layers of material in each of the tabs to be simultaneously welded together, while maintaining the tabs free from each other.
The ability to interpose a non-weldable insulated element, from paper or plastic material, between respective layers of weldable fabric is not obvious from the prior art, although there has been disclosed the concept of interposing a pattern-like sheet between a vibratory tool and the layers of material to be joined, in a manner described in U.S. Pat. No. 3,817,802. Applicants have advanced the art by now discovering that the ultrasonic vibratory energy can be applied to a first layer of overlapping sheets of material, and that this energy is capable of then continuing through an insulation element, to a second layer of overlapping sheets of material. Applicants have also discovered that the insulation element may be of minimal thickness, such that it is easily severed or cut simultaneously with the overlapping sheets on the opposite sides thereof.
While the instant invention will be primarily described in conjunction with the manufacture of articles to be utilized as brassiere tapes, it will be apparent that the same principles disclosed herein may be applied to other articles formed in a continuous strip having overlapping layers of fabric, or material, in which a pair of tabs or other protrusions extend therefrom for subsequent utilization for securement to a garment or other end product.